Field
Certain embodiments may broadly apply to communication system, such as communication systems associated with the long term evolution (LTE) of the third generation partnership project (3GPP). Certain embodiments more particularly may be relevant to eliminating or reducing transmission of common signals for enhanced spectral efficiency, improved support for heterogeneous networks, network energy saving possibilities, and the like.
Description of the Related Art
In wireless communication systems, downlink reference signals are normally created to provide reference for time and frequency synchronization and channel estimation used in coherent demodulation as well as a reference for a channel quality measurement used in multi-user scheduling and for handover decisions. In the LTE Release 8 (Rel-8) specification, one single type of downlink reference format called a cell-specific reference signal (CRS) is defined for synchronization, channel estimation and channel quality measurement. The characteristics of Rel-8 CRS include that, regardless of multiple input, multiple output (MIMO) channel rank that a user equipment (UE) actually needs, the base station can always broadcast the CRS to all UEs based on the largest number of MIMO layers/ports.